A vehicle “consist” is group of two or more vehicles mechanically and/or logically coupled or linked together to travel along a route. For example, a rail vehicle consist is a group of two or more rail vehicles that are mechanically coupled or linked together to travel along a route, as defined by a set of rails that support and guide the rail vehicle consist. One type of rail vehicle consist is a train, which may include one or more locomotives (or other powered rail cars/vehicles) and one or more non-powered rail cars/vehicles. (In the context of a rail vehicle consist, “powered” means capable of self propulsion and “non-powered” means incapable of self propulsion.) Each locomotive includes traction equipment for moving the train, whereas each rail car is configured for hauling passengers or freight. A consist may also include a group of two or more vehicles that are logically but not mechanically connected to travel along a route, e.g., coordinated control of non-mechanically linked vehicles, using wireless communications.
The rail vehicles in the consist, most typically the locomotives, may be outfitted with various functional components and systems, such as throttling, steering, braking and tractive effort/adhesion control systems. Typically, each locomotive in the consist is outfitted with an air compressor that produces a supply of pressurized air for use by one or more of these systems. The compressed air is typically stored in a main reservoir on-board each locomotive and the main reservoirs are fluidly coupled to one another through a main reservoir equalizing pneumatic trainline running throughout the length of the consist.
When compressed air is needed to perform a function such as braking or to increase tractive effort, the air may be drawn from the respective main reservoir by the system performing the desired function. For example, existing tractive effort/adhesion control systems direct a flow of compressed air from the main reservoir to a nozzle pointed at the contact surface of the rail to clean the rail of snow, ice or debris to increase adhesion/tractive effort. It has been shown that higher air flow to the nozzle of a tractive effort system translates into more rail vehicle tractive effort. Notably, however, existing tractive effort systems may consume air at a higher rate than the typical rail vehicle air compressor capability but generally within the capability of a multi-locomotive power consist.
Accordingly, there is a need for an adhesion control system and method for use with a rail vehicle that optimizes air use and compression.